Coherent structures in localized and global pipe turbulence.
Coherent structures in localized and global pipe turbulence.
复制标题
局部和整体管道湍流中的相干结构。
DOI：
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发表时间：
2007
影响因子：
8.6
通讯作者：
R. Kerswell
中科院分区：
文献类型：
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作者：
A. Willis;R. Kerswell
最近在管流中发现的不稳定行波(TW)被誉为一项重大突破，有望将它们填充到湍流吸引子中。通过数值模拟，我们证实了相干态的存在，这些相干态的内部快慢条纹在结构和能量上都与已知的行波相称。然而，这些只发生在低雷诺数(Re=2000-2400)的(局部化)“喷流”湍流的能量较低的区域内，而在Re=2800的(均匀)“弹状”湍流中则完全不发生。这强烈地表明，所有目前已知的TW都位于层流态和湍流态之间的相空间的中间区域，而不是嵌入到湍流吸引子本身中。相反，具有强减速核心的新的相干快条纹状态似乎填充在湍流吸引子中。
The recent discovery of unstable traveling waves (TWs) in pipe flow has been hailed as a significant breakthrough with the hope that they populate the turbulent attractor. We confirm the existence of coherent states with internal fast and slow streaks commensurate in both structure and energy with known TWs using numerical simulations in a long pipe. These only occur, however, within less energetic regions of (localized) "puff" turbulence at low Reynolds numbers (Re=2000-2400), and not at all in (homogeneous) "slug" turbulence at Re=2800. This strongly suggests that all currently known TWs sit in an intermediate region of phase space between the laminar and turbulent states rather than being embedded within the turbulent attractor itself. New coherent fast streak states with strongly decelerated cores appear to populate the turbulent attractor instead.